Process for producing coarse crystalline ammonium sulphate and product thereof



1 that the additional substances hitherto proposed ous ammonia so thatthe lye always contained 80 25 advantageous to add to this lye 2 to 3parts of sulphate, 80 grs. free sulphuric acid and 20 grs. 50

UNITED STATES PATENT OFFICE PROCESS FOR PRODUCING COARSE CRYS- TALLINEAMMONIUM SULPHATE AND PRODUCT THEREOF Andreas von Kreisler,Frankfort-on-the-VMain,

Germany No Drawing. Application August 26, 1933, Serial No. 687,006. InGermany August 29, 1932' 12 Claims. (Cl. 23119) troughs. All theseprocesses preclude continuproperties. The greater part of the carbamide15 ans work in a saturator or require expensive remains dissolved inthe'mother lye and must plants. only be renewed from time to time. Thesepa It has likewise been proposed, to assist the rated ammoniumsulphate crystals contain carformation of crystals of ammoniumsulphateby bamide in quantities from 0.1 to 0.5%.

adding foreign substances such as naphthalene, Examples 1. 2 parts ofcarbamide were added to 100 parts pure ammonium sulphate. When employedfor of lye in a saturator, which is operated with a fertilizing, it hasto be taken in consideration sulphuric acid of 60 B. and concentratedgasedo not possess any favorable vegetable physiogrs. of free acid perlitre. The ammonium sultllizmg va ue of the ammonium sulphate method,without the addition of carbamide It has been found that ammoniumsulphate in yielded, however, fine crystalline powder coa se crystals isobtained 1f the crystallization is 2 A lye containing to 100 parts ofammonium s bamide may be added to the sulphuric acid becarbamide per 100parts of salt. The saturator conditions of concentration. added to thelye in equivalent quantities. The

carbamide. The lye is then evaporated. This carbamide per litre ofwater. The lye was then evaporation may be carried out in a vacuum. Itfiltered at 100 C. and the 1 grs. ammonium The addition of carbamide,proposed according to the invention, exerts an excellent, always uniforminfluence upon the growth of the ammonium sulphate crystals in verydifferentshapes. The form of the crystals depends upon the temperatureof crystallization, the concentration of the solution, the coolingspeed, acid in the solution and upon other conditions. Moreover, thecarbamide is advantageously distinguished from other thereby that it hasno doubtful or detrimental vegetable physiological properties, but isitself an excellent fertilizer. v

The coarse crystalline ammonium sulphate obtained according to thepresent process is therefore not contaminated by any foreign substances,Which might detrimentally affect its employment for fertilizingpurposes, and at the same time capable of adhesion and being strewn.

I claim:----

1. A process for the production of coarse crystalline ammonium syntheticammonia, consisting in crystallizing the ammonium sulphate from itsaqueous solution with addition of 2 to 6 parts of carbamide per 100parts of ammonium sulphate.

2. A process for the production of coarse crystalline ammonium sulphatefrom synthetic am.- monia, consisting in adding 1 to 10 parts of car-100 parts of a solution of ammonium sulphate, and in bringing tocrystallizing the ammonium sulphate whilst continually adding syntheticammonia and sulphuric acid. V

3. A process for the production of coarse crysconsisting in adding 1 to10 parts of car- 100 parts of a solution of ammonium and continuallyadding synthetic ammonia and sulphuric acid in such quantities that thelye is permanently maintained at its initial concentrations.

talline ammonium sulphate from synthetic ammonia, consisting in phate inwater, in adding 1 to 10 bamide to 100 parts of the solution, tallizingthe solution.

parts of carand in crystalline ammonium sulphate from synthetic am-.

i 4. A process for the production of coarse crys- V dissolving ammoniumsul- 5. A process for the production of coarse crystalline ammoniumsulphate from synthetic ammonia, consisting in crystallizing undersuperatmospheric pressure the ammonium sulphate from its aqueous partsof carbamide per 6. A process for the production of coarse .crys-'talline ammonium sulphate from synthetic ammonia, consisting incrystallizmg under reduced pressure the ammonium sulphate from itsaqueous solution whilst adding 1 to 10 parts of carbamide per 100 partsof the solution.

7. A process for the production of coarse crystalline ammonium sulphatefrom synthetic ammonia, consisting in crystallizing the ammoniumsulphate from its aqueous solution whilst adding 1 to 10 parts ofcarbamide per 100 parts of the solution and introducing steam.

8. A process for the production of coarse crystalline ammonium sulphatefrom synthetic ammonia, consisting in crystallizing the ammoniumsulphate from its aqueous solution Whilst adding 1 to 10 parts ofcarbamide to 100 parts of ammonium sulphate.

9. A process for the production of coarse crystalline ammonium sulphatefrom synthetic ammonia, consisting in adding 2 to bamide to each 100parts of ammonium sulphate solution, in crystallizing the solution andin continually adding synthetic ammonia and sulphuric acid in sufficientquantities to maintain the lye at its initial concentration.

10. A process for the production of coarse cryssynthetic amtallineammonium sulphate from monia, consisting in crystallizing sulphate froma solution containing 100 parts of Water, 2 to '8 parts of freesulphuric'acid and 2 to 3 parts of carbamide monium sulphate. 7

ll. Coarse crystalline ammoniumsulphate characterized by a content ofcarbamide of 0.1 to 0.5% in fine distribution. 1 '12. Ammonium sulphatein coarse crystals characterized by a content of carbamide of less than0.5970.

' ANDREAS VON KREISLER' the ammonium 6 parts of carper 100 parts of am-

